If you want to do modifications in class for example, you need to go setup--> classes --> search all classes and then edit the class.It takes a lot of time.
In Google chrome,we have a plugin which helps searching a class or page easier.
Use this plugin,really very useful.
step 1) search "sfdc advanced code search plugin for chrome"
You will get the screen as shown below.
step 2) Click on the first link.You will get a screen as shown below.
step 3) add this plugin .Once you add this plugin ,you will be able to view a screen as shown in the image below.
Now you can search for classes or pages or a string in your code.